Prevalence of Beijing genotype family of Mycobacterium tuberculosis isolated in Henan province and its correlation with drug-resistance

Objective To understand the status of drug-resistance of Mycobacterium tuberculosis (M.tuberculosis) isolated from Weishi,Henan province,and its correlation with Beijing genotype family.Methods The drug susceptibility of the clinical isolates of M.tuberculosis was determined by proportion method and the genotypes were identified by RD105 deletion test.The statistical analysis was performed with χ² test.Results Among 164 clinical isolates of M.tuberculosis,126 strains(76.8%) were sensitive to 4 first line anti-tuberculosis drugs,including isoniazid(INH),rifampicin(RFP),streptomycin(SM),and ethambutol(EMB),whereas 38 strains(23.2%) were resistant to the 4 drugs,in which 14 strains(8.5%) were single drug-resistant and 13 strains(7.9%) belonged to multi-drug resistance(MDR).The percentages of drug resistance to INH,SM,RFP,and EMB were 16.5% (27/164),15.9% (26/164),9.1% (15/164),and 7.3% (12/164),respectively.As demonstrated by genotyping,147 strains of 164 M.tuberculosis isolates(89.6%) belonged to Beijing family and others were non-Beijing family.Among the 147 Beijing family strains,36 strains (24.5%) were drug-resistant,and 111 strains(75.5%) were sensitive.Among 17 non-Beijing family strains,2 strains(11.76%) were drug-resistant and 15 strains (88.23%) were sensitive.Concerning to the drug-resistance,there was no significant difference between the Beijing family strains and the non-Beijing family(χ²=0.05,P> 0.05).Conclusion The status of drug-resistance of M.tuberculosis in Henan is serious and no correlation exists between the drug-resistance of M.tuberculosis and Beijing family genotypes.